Traffic lights have been with us for a long time. And, they, like automobiles, have gone from being an oddity and a rarity, at the beginning of this century, to being a virtual necessity. At the same time traffic lights have become increasingly complex. Integrating a traffic light into an entire traffic control system has necessitated interconnecting traffic signals electronically to properly coordinate vehicular and pedestrian traffic at specific intersections as well as to properly coordinate vehicle traffic between intersections.
Advertising displays directed to motorists to promote merchants' products and services are, of course, also very common, usually in the form of highway billboards, signage along streets, and store front displays. There are some very good reasons to combine advertising displays with traffic signals. For example, traffic control signals are usually placed at intersections where there is a high volume of vehicular traffic, so advertising at those same intersections would get exposed to many people, usually at times when the people can do little else other than to drive or ride in the vehicle. Revenues from the rental of such advertising space on traffic signals could be put to good use by local governments for road and street improvements or other desirable community improvements or expenditures. There may also be some very real benefits in providing advertising displays to occupy drivers' minds and attentions to decrease boredom and irritability while the wait at red lights or are stalled in congested traffic.
Unfortunately, there are also some safety concerns, as well as practical considerations, that have thus far prevented any wide-spread or even minimal general use of advertising displays in conjunction with traffic signals in the past. One of the most significant safety problems is that the advertising displays could tend to divert drivers' attentions from the traffic control signals and from observing surrounding vehicular and pedestrian traffic at busy intersections when their utmost attention to their driving is needed to avoid traffic congestion and even possible accidents. Also, the physical locations of many traffic signals adjacent, and often over, busy streets and walkways presents a problem in changing the advertising displays during normal business hours without impeding the flow of traffic.
There are a few examples of earlier attempts to combine advertising displays with traffic signals, which have never attained any significant use, probably because they did not solve the safety and practical problems discussed above. For example, U.S. Pat. No. 1,662,348, issued to G. Stricker in 1928, discloses a large, framed, box-like mounting structure that contains both set of red, amber, and green traffic signal lights and an illuminated advertising display. The advertising display portion of Stricker's apparatus contained a semitransparent surface mask or screen having advertising printed thereon along with a set of back lights to illuminate the advertising mask or screen from behind. Stricker apparently tried to minimize the problem of diverting drivers' attentions from the stop, go, and caution messages intended to be conveyed by the conventional red, green, and amber traffic lights by providing corresponding red, green, and amber back lighting for illuminating his advertising displays. Unfortunately, such color-coordinated backlighting still presented the advertising to the drivers at all times. While the U.S. Pat. No. 2,503,574, issued to J. Allen in 1950, disclosed an advertising display that is positioned in sidewalk curbs rather than adjacent the vehicular traffic control lights, it presents the same kind of problem to both pedestrians and to drivers who are in a position to see such displays. In fact, this Allen device really exacerbates the safety problem, because it combines and makes the "STOP" and "GO" signals integral parts with the advertising message. Such combination could actually confuse people and camouflage the intended traffic control message in the advertising message, thus, losing, or at least diluting, the crisp significance of the traffic control message.